Thin-film deposition by rear-side laser ablation has been reported as a new configuration for transparent materials. In order to study the features of this configuration, characterization of the rear-side and front-side plasmas was performed. Experiments were carried out in a low vacuum (50 Tort), using SiO2 targets and a Nd:YAG laser as the energy source. The shock wave associated with rear- and front-side ablation plumes were recorded by shadowgraphy and the corresponding velocities were determined in each case. We found a spherical wave front in both cases. Optical emission spectroscopy (OES) was carried out in order to identify the excited species present in each plasma. (C) 2002 Elsevier Science B.V. All rights reserved.